document.write( "Question 937832: A boat went a certain distance up a river and back in 2 hours and 56 minutes. Its speed was 17.5 mph going upriver and 21 mph returning. How far up the river did it go ?
\n" ); document.write( "can you please give an equation and detailed explanation \n" ); document.write( "

Algebra.Com's Answer #571220 by josmiceli(19441) $\"\"$ $\"About$

You can put this solution on YOUR website!
Let $\"+d+\"$ = the one-way distance ( up or down river )
\n" ); document.write( "Let $\"+t+\"$ = time in hrs to go upriver
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\n" ); document.write( "Convert $\"+56+\"$ min to hours
\n" ); document.write( " $\"+56%2F60+=+.9333+\"$ hrs
\n" ); document.write( " $\"+2.9333+-+t+\"$ = time in hrs to go downriver
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\n" ); document.write( "Equation for going upstream:
\n" ); document.write( "(1) $\"+d+=+17.5t+\"$
\n" ); document.write( "Equation for going downstream:
\n" ); document.write( "(2) $\"+d+=+21%2A%28+2.9333+-+t+%29+\"$
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\n" ); document.write( "Substitute (1) into (2)
\n" ); document.write( "(2) $\"+17.5t+=+21%2A%28+2.9333+-+t+%29+\"$
\n" ); document.write( "(2) $\"+17.5t+=+61.6+-+21t+\"$
\n" ); document.write( "(2) $\"+38.5t+=+61.6+\"$
\n" ); document.write( "(2) $\"+t+=+1.6+\"$ hrs
\n" ); document.write( "Plug this result back into (1)
\n" ); document.write( "(1) $\"+d+=+17.5%2A1.6+\"$
\n" ); document.write( "(1) $\"+d+=+28+\"$
\n" ); document.write( "The boat went 28 mi upriver
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\n" ); document.write( "check:
\n" ); document.write( "(2) $\"+d+=+21%2A%28+2.9333+-+t+%29+\"$
\n" ); document.write( "(2) $\"+28+=+21%2A%28+2.9333+-+1.6+%29+\"$
\n" ); document.write( "(2) $\"+28+=+61.6+-+33.6+\"$
\n" ); document.write( "(2) $\"+28+=+28+\"$
\n" ); document.write( "OK \r
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